Saint Michael's Church is the oldest extant religious site in Luxembourg City. The first church was built on the site in 987 as the castle chapel for the Count of Luxembourg. However, over the following centuries, the building was destroyed, rebuilt, and renovated several times. Its current appearance dates to 1688, and unites Romanesque and Baroque architectural styles, pre-dating the national Moselle Baroque style. The building has been restored since then, preserving its original form.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.